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Biomedical subjects

C E Lambert

Publications and source records attributed to C E Lambert.

At least 19 recordsLinked to original sources
PubMed2001

Literature review of role stress/strain on nurses: an international perspective.

The presence of role stress/strain among nurses has been of concern throughout the world. However, to date, no one has conducted, from an international perspective, a literature review of research on the topic. This article assesses research from 17 countries, identifies the major areas of focus in the studies, compares and contrasts the findings, summarizes the state of the science on role stress/strain on nurses and makes recommendations for future research.

Burnout, Professional↗
PubMed1999

Psychological hardiness: state of the science.

Over the past 20 years there has been increasing interest in the concept, psychological hardiness. Hardiness is defined as a constellation of attitudes, beliefs, and behavioral tendencies that consist of three components: commitment, control, and challenge. The article presents a review and assessment of more than 50 journal publications on hardiness that have appeared since 1987. A presentation of the conceptualization of hardiness and the state of the science of hardiness is presented. Limitations in the current science of hardiness are delineated. These limitations include the identification of: factors related to conceptualization and instrumentation, the types of hardiness studies lacking in the current literature, and the types of subjects rarely used in hardiness research.

Adaptation, Psychological↗
PubMed1991

Calbindin-D28K (CaBP) levels and calcium currents in acutely dissociated epileptic neurons.

Nerve cells that lack the cytoplasmic Ca2+ binding protein Calbindin-D28K (CaBP) appear to be selectively vulnerable to Ca(2+)-related injury consistent with a postulated intraneuronal Ca(2+)-buffering role of CaBP. We have confirmed the selective loss of CaBP from the dentate gyrus during kindling-induced epilepsy in acutely dissociated granule cells (GCs) from kindled rats. Immunohistochemically stained kindled neurons showed a significant loss of CaBP when compared to controls (p less than 0.001; ANOVA). The Ca(2+)-buffering role of CaBP was assessed in acutely dissociated control and kindled GCs by examining a physiological process highly sensitive to intracellular Ca(2+)-buffering: the Ca(2+)-dependent inactivation of high-voltage activated (HVA or L-type) Ca2+ currents in the absence (or presence) of exogenous Ca(2+)-chelators. Whole-cell patch clamp recordings in kindled GCs demonstrated a markedly enhanced Ca(2+)-dependent inactivation of Ca(2+)-currents. After brief conditioning Ca2+ currents, in the absence of an exogenous intraneuronal Ca(2+)-chelator, subsequent test Ca2+ currents were inactivated by 58.3% in kindled GCs, a significant increase from the 37.4% inactivation observed in control GCs (p less than 0.005; ANOVA). The differential Ca2+ current decay and Ca(2+)-dependent inactivation were prevented in both control and kindled GCs upon loading the neurons with the exogenous Ca(2+)-chelator BAPTA. These experiments demonstrate a high correlation between the loss of CaBP and changes in Ca2+ current inactivation and are consistent with the hypothesis that CaBP contributes to the physiological Ca(2+)-buffering in mammalian neurons.

Animals↗
PubMed1990

Relationships among hardiness, social support, severity of illness, and psychological well-being in women with rheumatoid arthritis.

The purpose of this study was to examine the relationships among hardiness, social support, severity of illness, and psychological well-being in women with rheumatoid arthritis who were being seen on an outpatient basis. Questionnaires were administered, to 122 women, assessing hardiness, social support, and psychological well-being. Severity of illness was determined by assessment of joint function, sedimentation rates, and length of morning stiffness. Significant correlations were found between (a) hardiness and the number of persons in the social support system, (b) hardiness and satisfaction with social support, (c) hardiness and psychological well-being, (d) the number of persons in the social support system and satisfaction with social support, (e) the number of persons in the social support system and joint function, (f) satisfaction with social support and psychological well-being, and (g) length of morning stiffness and psychological well-being. Stepwise regression analysis indicated that satisfaction with social support, hardiness, and length of morning stiffness (in that order) were the best predictors of psychological well-being. The findings suggest that these three factors play a significant role in the identification of women with rheumatoid arthritis who are more able to cope with the stressful ramifications of their disease.

Activities of Daily Living↗
PubMed1990

Enantioselective S-oxygenation of para-methoxyphenyl-1,3-dithiolane by various tissue preparations: effect of estradiol.

Liver, kidney, and lung microsomes prepared from nonpretreated female Sprague-Dawley rats catalyze the NADPH- and oxygen-dependent S-oxygenation of para-methoxyphenyl-1,3-dithiolane. Studies on the biochemical mechanism of dithiolane S-oxygenation in liver, kidney, and lung microsomes suggest that this reaction is catalyzed in a diastereoselective and enantioselective fashion by the flavin-containing monooxygenase and, to a lesser extent, the cytochromes P-450. This conclusion is based on results examining the effects of selective cytochrome P-450 inhibitors and positive effectors, microsome heat-inactivation treatment, and alternate substrates for the flavin-containing monooxygenase. Liver and kidney microsomes prepared from ovarectomized female rats tended to have decreased S-oxygenase activity, compared with nonpretreated female rats, whereas ovarectomized rats pretreated with estradiol had markedly lower S-oxygenase activity. In contrast, lung microsomal S-oxygenase activity, which is low in pulmonary microsomes from nonpretreated female rats, increases 2-4-fold after ovariectomization and estradiol pretreatment. In female Sprague-Dawley rats, estradiol pretreatment is mainly responsible for the large decrease (or increase) in S-oxygenase activity observed in the tissues examined, although it is unlikely that estradiol alone controls flavin-containing monooxygenase S-oxygenase activity.

Animals↗
PubMed1989

Effects of MPTP, MPP+ and paraquat on mitochondrial potential and oxidative stress.

The effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 1-methyl-4-phenylpyridinium (MPP+) and 1,1-dimethyl-4,4-bipyridinium (paraquat) upon the electrical potential across the plasma and mitochondrial membranes within synaptosomes has been investigated. MPTP selectively depressed plasma membrane potential while MPP+ specifically reduced mitochondrial potential. The structurally similar compound paraquat had no effect on either membrane potential. Enhancement of the lipid peroxidative activity with an Fe-ADP complex depressed both potentials. Paraquat effected increased peroxidative activity in brain homogenates that was less pronounced than that due to Fe-ADP. MPTP reduced basal but stimulated Fe-ADP enhanced peroxidation. The mechanisms underlying the toxicity of MPP+ are likely to differ from those of paraquat, primarily involving impaired mitochondrial function rather than increased oxidative stress.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1989

Social support, hardiness and psychological well-being in women with arthritis.

The purpose of this study of women with rheumatoid arthritis (n = 12) was to determine whether or not social support and hardiness are predictors of psychological well-being when the severity of the women's rheumatoid arthritic disease process is statistically controlled. The findings suggest that satisfaction with social support and hardiness are indeed significant predictors of psychological well-being in women with rheumatoid arthritis, regardless of the severity of illness.

Adult↗
PubMed1988

Role of formaldehyde hydrazone and catalase in hydrazine-induced methylation of DNA guanine.

Hydrazine is acutely neurotoxic, hepatotoxic and nephrotoxic; it is also carcinogenic to liver and lung in rodents. Administration of hydrazine results in formation of 7-methylguanine and O6-methylguanine in target organ DNA of rats, mice, hamsters and guinea-pigs. It has been suggested that hydrazine reacts with endogenous formaldehyde to form a condensation product which could be metabolized to a methylating agent. Solutions of 0.50 mM hydrazine and formaldehyde have, upon mixing, NMR spectra (300 MHz) consistent with the formation of formaldehyde hydrazone but not other possible condensation products such as tetraformyltriazine or formaldehyde azine. These same solutions evidencing hydrazone formation, when incubated in an in vitro system containing post-mitochondrial (S9), microsomal, cytosolic or mitochondrial cell fractions, resulted in the methylation of DNA guanine; S9 was the most active fraction. Neither the P-450 monooxygenase nor flavin monooxygenase systems appeared to be important in hydrazine/formaldehyde-induced methylation of DNA. However, sodium azide, cyanamide and carbon monoxide all inhibited S9-supported DNA methylation. Bovine liver catalase, a heme-containing cytochrome, readily transformed hydrazine/formaldehyde to a methylating agent. The data support formation of formaldehyde hydrazone as the condensation product of hydrazine and formaldehyde which is rapidly transformed in various liver cell fractions, perhaps by catalase and/or catalase-like enzymes, to a methylating agent.

Amines↗
PubMed1988

A review and synthesis of the research on role conflict and its impact on nurses involved in faculty practice programs.

A review of the literature is presented that offers an overview of state-of-the-art research on role conflict and its impact on nurses involved in faculty practice programs. The literature is described in terms of: 1) where the research has been reported; 2) who the researchers have been and from what discipline they have come; 3) the major theoretical perspectives used; 4) the unit of analysis studied; and 5) the research methods used.

Faculty, Nursing↗
PubMed1987

Psychosocial impacts created by chronic illness.

One can ascertain, from this brief overview, that chronic illness can and does abuse an afflicted person's psychologic well-being, body image, sexuality, social identity, and occupational role. However, the alterations imposed on the chronically ill person by the disease can be dealt with in an effective manner. Health care providers need to examine with each patient what alterations are occurring, what changes might occur, and how the patient might effectively contend with and control each of these alterations. Although chronic illness is intrusive, it can be dealt with in an effective manner so that the afflicted person can lead a productive life.

Adaptation, Psychological↗
PubMed1987

Coping with rheumatoid arthritis.

Rheumatoid arthritis, a chronic systemic connective tissue disorder that affects women three times more often than men, that is of unknown cause, and that involves inflammatory changes primarily in the small peripheral joints of the hands and feet, afflicts approximately 8 million people in the United States. In its mildest form, rheumatoid arthritis causes little interference with normal activity. However, in its severest form, it can render the afflicted person bound to a wheelchair, house, or even a bed. As a result of its crippling effects, simply accomplishing the tasks of daily living can be a feat for some people. Coping with the existence of pain, disabling effects, and/or deformities brought on by rheumatoid arthritis is not an easy task for the afflicted person. To cope with the physical aspects of the disease, the afflicted person is likely to use the coping mechanisms of information seeking, direct action, inhibition of action, intrapsychic processes, and social support. Which coping mechanisms are used, how the mechanisms are used, and how effective the mechanisms are, must be determined by the nurse so that appropriate psychosocial interventions can be planned and implemented.

Adaptation, Psychological↗
PubMed1986

The role of formaldehyde in hydrazine-induced methylation of liver DNA guanine.

Administration of the hepatotoxin and carcinogen, inorganic hydrazine, to rodents results in the formation of 7-methylguanine and O6-methylguanine in liver DNA; co-administration of [methyl-14C]methionine or [14C]formate with the hydrazine labels the methylguanines, suggesting involvement of the 1-carbon pool in the methylation process. The present study investigates the proposal that the methylation mechanism involves reaction of hydrazine with endogenous formaldehyde to yield formaldehyde hydrazone, which could be metabolized to the potent methylating agent diazomethane. Hamsters were pretreated with methanol, ethanol or cyanamide to alter the endogenous hepatic aldehyde levels prior to administration of hydrazine. Formaldehyde levels were refractory to the pretreatments; hepatic acetaldehyde levels were increased, but hydrazine administration under such conditions did not result in the formation of ethylated guanines in DNA. Methanol and ethanol inhibited hydrazine-induced methylation of DNA. Hydrazine incubated with liver S9 fraction and calf thymus DNA induced the formation of 7-methylguanine and O6-methylguanine when formaldehyde was present in the incubation system; substitution of formaldehyde with acetaldehyde in the incubation medium did not result in any detectable alkylation of DNA. Both liver microsomal and cytosolic fractions demonstrated heat-labile activity in supporting the hydrazine-induced methylation process. Tetraformyltrisazine, or a similar reaction product of hydrazine and formaldehyde, may be a more important intermediate than formaldehyde hydrazone in the hydrazine-induced methylation of DNA.

Aldehydes↗
PubMed1986

Tetraformyltrisazine and hydrazine-induced methylation of liver DNA guanine.

Hydrazine induces methylation of target-organ DNA guanine; the methylation mechanism was proposed to involve reaction of hydrazine with endogenous formaldehyde. One possible condensation product of hydrazine and formaldehyde is tetraformyltrisazine (TFT). TFT administered to Sprague-Dawley rats produced 7-methylguanine and O6-methylguanine in liver DNA at rates of formation and times to maximal methylguanine levels similar to those observed after hydrazine administration. TFT administration, however, resulted in greater amounts of methylguanines than did hydrazine on a molar basis, suggesting that TFT is perhaps a more proximal intermediate in hydrazine-induced methylation. The metabolic activation of TFT and hydrazine-plus-formaldehyde to methylating intermediates was detectable in in vitro systems containing as little as 0.2 mM TFT or 1 mM hydrazine-plus-formaldehyde, the lowest concentrations yet tested. The other major condensation product of hydrazine and formaldehyde, formalazine, also methylated liver DNA in vivo, but this polymer forms under conditions that would not be expected under in vivo administration of hydrazine. A novel pathway is proposed for the generation of a carbocation in hepatocytes exposed to hydrazine, consisting of condensation of hydrazine and formaldehyde to form TFT or formaldazine and/or formaldehyde hydroxymethylhydrazone and involves methylazomethanol as an intermediate.

Alkylating Agents↗